# Why doesnt as3 throw an error with addEventListener(string, function)

**URL:** <https://forum.kirupa.com/t/why-doesnt-as3-throw-an-error-with-addeventlistener-string-function/279421>\
**Category:** flash\
**Created:** [January 14, 2009, 4:07pm UTC](https://forum.kirupa.com/t/why-doesnt-as3-throw-an-error-with-addeventlistener-string-function/279421 "2009-01-14T16:07:28Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![furyan\_be](https://avatars.discourse-cdn.com/v4/letter/f/3da27b/32.png) [@furyan\_be](https://forum.kirupa.com/u/furyan_be)\
**Post date:** [January 14, 2009, 4:07pm UTC](https://forum.kirupa.com/t/why-doesnt-as3-throw-an-error-with-addeventlistener-string-function/279421/1 "2009-01-14T16:07:28Z")

</div>

Hi

the callback function uses a parameter from the Event type, but why doesnt as3 give an error when you type

addEventListener(“click”, func);

function func(event:Event):void  
{

}

func needs an argument from the type Event, but how does as3 ignore this?